KR20030034601A - Target detection circuit - Google Patents

Abstract

PURPOSE: A target detection circuit is provided to detect the target signal by stably operating the automatic gain control circuit by using the target signal stored when another signal shields the target signal and divided by previously memorizing the size of the target signal so as to operate the automatic gain control circuit with reference to the size of the target signal. CONSTITUTION: A target detection circuit provided with a first amplifier(111) for amplifying a first target signal inputted thereto, a second amplifier(112) for amplifying a first flare signal having the same size with the first target signal, a switching device for varying the amplification level in response to the signal inputted from the outside by feeding back the signal outputted from the first amplifier(111) and an attenuator(114) keeping the output constant by controlling the gain of the first amplifier(111) and the second amplifier(112) by maintaining the signal outputted from the switching device with constant includes a target signal detection circuit(120) for converting the pulse by receiving the first target signal and the first flare signal in response to the control signal inputted thereto, adding the two converted signals and outputting the second target signal by comparing the added signal with a reference signal, an initial threshold voltage generation circuit(130) for outputting the initial threshold voltage as a direct voltage of a constant level in response to the initial gain setting of the user, a flare signal detection circuit(140) for comparing the peak value detected by the peak value of the first target signal outputted from the target signal detection circuit(120) by the control signal inputted thereto with the initial threshold voltage outputted from the initial threshold voltage generation circuit(130) and for outputting the compared result as a second flare signal and a logic circuit(150) for controlling the amplification level of the switching device of the automatic gain control circuit by adding two signals outputted from the target signal detection circuit(120) and the flare signal detection circuit(140).

Description

Target detection circuit {TARGET DETECTION CIRCUIT}

The present invention relates to a target detection circuit. More particularly, the present invention relates to a target detection circuit, and more particularly, when auto-gain control is performed based on the size of a specific signal when another signal of the same size is input later and two signals are separated. The present invention relates to a target detection circuit for performing only detection of a specific signal.

In general, when a target signal is detected, when a flare signal, which is the same noise component as the target signal, is generated and the signal covers the target signal, the automatic gain control circuit operates based on another signal having the same size. It became.

However, even after the target signal and other signals are separated, the size of the target signal is very weak due to the gain of the automatic gain control circuit, which causes a problem of missing the target signal.

Accordingly, an object of the present invention is to solve the above problems, and when another signal obscures and separates the target signal by previously storing the size of the target signal in order to operate the automatic gain control circuit based on the size of the target signal. In addition, the automatic gain control circuit is stably operated using the stored target signal to detect the target signal.

1 is a block circuit diagram schematically showing the configuration of a target detection circuit according to the present invention;

2 is a waveform diagram showing a waveform of a signal output from each component of the target detection circuit according to the present invention;

<Explanation of symbols for main parts of the drawings>

110: automatic gain control circuit 113: field effect transistor

120: target signal detection circuit 121: half-wave rectifier

122: first peak detector 123, 124: first and second switch

125: adder 126: first comparator

130: initial threshold voltage generation circuit 140: flare signal detection circuit

141: second peak detector 142: second comparator

150: logic circuit

Features of the present invention for achieving the above object,

A first amplifier for amplifying the input first target signal, a second amplifier for amplifying a first flare signal having the same magnitude as the first target signal, and a signal output from the first amplifier to be fed back from the outside Automatic gain consisting of a switching element for varying the amplification level in accordance with the signal, and an attenuator for maintaining the output of the first amplifier and the second amplifier by maintaining the signal output from the switching element at a constant level to adjust the gain of the first amplifier and the second amplifier In the target detection circuit including an adjustment circuit,

A target signal detection circuit that receives the first target signal and the first flare signal by inputting the control signal, converts the signals into pulses, adds the two converted signals, and compares them with a reference signal to output a second target signal. Wow,

An initial threshold voltage generation circuit for outputting an initial threshold voltage which is a DC voltage of a predetermined level according to a user's initial input gain setting by an input control signal;

A second flare by comparing the detected peak value with an initial threshold voltage output from the initial threshold voltage generation circuit as a reference signal by detecting a peak value of the first target signal output from the target signal detection circuit by an input control signal A flare signal detecting circuit for outputting a signal;

And a logic circuit for controlling the amplification level of the switching element of the automatic gain control circuit by adding two signals output from the target signal detection circuit and the flare signal detection circuit.

Here, the target signal detection circuit,

A half wave rectifier for receiving the first flare signal having a sinusoidal shape and rectifying the half wave;

A first peak detector for detecting a peak value of the signal output from the half-wave rectifier;

A first switch which is switched according to an input control signal and converts a signal output from the first peak detector into a pulse wave form and outputs the pulse wave;

A second switch switched according to an input control signal to convert the first target signal into a pulse wave form and output the pulse signal;

An adder for adding and outputting signals input from the first switch and the second switch;

And a first comparator configured to output a second target signal, which is a difference between the two signals, by comparing the pulse type signal output from the adder and the reference signal.

Here, the flare signal detection circuit,

A second peak detector for detecting a peak value of a signal output from the first comparator of the target signal detection circuit according to an input control signal;

And a second comparator configured to compare a peak value detected by the second peak detector with an initial threshold voltage output from the initial threshold voltage generation circuit, which is a reference signal, to output a second flare signal that is a difference between the two signals.

Here, the second peak detector,

At least one capacitor and a resistor are provided to store the second target signal by lengthening the time constant.

Hereinafter, the configuration of the target detection circuit according to the present invention will be described in detail with reference to FIGS. 1 and 2.

1 is a block circuit diagram schematically showing the configuration of a target detection circuit according to the present invention, Figure 2 is a waveform diagram showing the waveform of the signal output from each component of the target detection circuit according to the present invention.

1 and 2, the target detection circuit 100 according to the present invention includes an automatic gain adjustment circuit 110, a target signal detection circuit 120, an initial threshold voltage generation circuit 130, and a flare. It consists of a signal detection circuit 140 and a logic circuit 150.

First, the automatic gain control circuit 110 includes a first amplifier 111, a second amplifier 112, a field effect transistor 113, and an attenuator 114.

The first amplifier 111 amplifies and outputs the input first target signal VIN2 (VOUT3), and the second amplifier 112 has a first flare signal VIN1 having the same size as the first target signal VIN2. Amplify and output (VOUT4).

The field effect transistor 113 feeds back the signal output from the first amplifier 111 to vary the amplification level according to the signal output from the logic circuit 150, and the attenuator 114 outputs from the field effect transistor 113. The signal is maintained at a constant level to adjust the gain of the first amplifier 111 and the second amplifier 112 to maintain a constant output.

The target signal detection circuit 120 includes a half-wave rectifier 121, a first peak detector 122, a first switch 123, a second switch 124, an adder 125, and a first Comparator 126.

The half-wave rectifier 121 receives the sinusoidal first flare signal VIN2 and outputs the rectified half-wave rectified signal V1.

The first peak detector 122 detects the peak value of the signal output from the half-wave rectifier 121.

The first switch 123 is switched according to the input control signal VIN3 to convert the signal V2 output from the first peak detector 122 into a pulse wave form and output the pulse wave, and the second switch 124 is input. The first target signal VIN2 is converted into a pulse wave form by being switched according to the control signal VIN3 to be outputted.

The adder 125 is operated according to the input control signal VIN3 to add and output a signal input from the first switch 123 and the second switch 124, and the first comparator 126 is an adder 125. The second target signal VOUT1, which is a difference between the two signals, is output by comparing the pulse type signal output from the reference signal with the reference signal 0V.

In addition, the initial threshold voltage generator circuit (Initial Threshold Generator) 130 is operated by the input control signal (VIN3) is an initial threshold voltage (V4) which is a DC voltage of a predetermined level according to the user's initial input gain (VIN4) setting Outputs Here, when the flare signal larger than the level of the target signal stored in the flare signal detection circuit 140 is input, the initial threshold voltage generation circuit 130 excludes the signal of the flare signal section from the flare signal detection circuit 140. In order to output the initial threshold voltage.

In addition, the flare signal detection circuit 140 includes a second peak detector 141 and a second comparator 142.

The second peak detector 141 detects the peak value V3 of the signal output from the first comparator 126 of the target signal detection circuit 120 according to the input control signal VIN3. Here, the second peak detector 141 includes a capacitor (not shown) and a resistor (not shown) to operate based on a fast charge time and a relatively slow discharge time, so that the magnitude of the target signal is detected quickly and the slow discharge is performed. Even if the flare signal obstructs the target signal by time, the target signal can be stored continuously.

The second comparator 142 compares the peak value V3 detected from the second peak detector 141 with the initial threshold voltage V4 output from the initial threshold voltage generation circuit 130 which is a reference signal, and thus the difference between the two signals. The second flare signal VOUT2 is output.

The logic circuit 150 controls the amplification level of the field effect transistor 113 of the automatic gain control circuit 110 by adding the two signals output from the target signal detection circuit 120 and the flare signal detection circuit 140. In this case, the OR gate is preferably used as the logic circuit 150, and any logic circuit that combines and outputs the second target signal VOUT1 and the second flare signal VOUT2 may be used.

Hereinafter, the operation of the target detection circuit according to the present invention will be described in detail with reference to FIGS. 1 and 2.

First, when a sine wave type first target signal VIN2 is input, it is converted into a pulse type signal through the second switch 124 of the target signal detection circuit 120 and input to the adder 125.

In this state, when the first flare signal VIN1 having a sinusoidal shape is input as shown in FIG. 2, the negative region waveform is shown in FIG. 2 through the half-wave rectifier 121 of the target signal detection circuit 120. After this rectification, the rectified signal V1 is input to the first peak detector 122 to detect a peak value of the signal rectified by the first peak detector 122 and output a peak signal V2. Then, this is again applied to the first switch 123 is converted into a pulse-shaped signal in the first switch 123 is input to the adder 125.

When a pulse type signal is output from the first switch 123 and the second switch 124, the adder 125 adds the two signals and outputs the two signals to the first comparator 126. The first comparator 126 compares the signal output from the adder 125 with the reference signal OV and outputs a second target signal VOUT1 in the form of a pulse that is a difference between the two signals. In this case, the pulse width may be varied according to the control signal VIN3 input to the first switch 123 and the second switch 124.

Meanwhile, the second target signal VOUT1 output from the first comparator 126 is input to the second peak detector 141 of the flare signal detection circuit 140. The second peak detector 141 is operated by the control signal VIN3 to detect the peak value of the second target signal VOUT1 to convert the peak signal V3 to the second comparator 142 as shown in FIG. 2. Output At this time, since the second peak detector 141 includes a capacitor and a resistor, the detected peak signal is maintained to some extent until the peak signal of the next period is detected. That is, the second target signal VOUT1 is stored.

Then, the second comparator 142 compares the peak signal V3 on the basis of the initial threshold voltage V4 output from the initial threshold voltage generation circuit 130 and compares the peak signal V3 with the second flare signal in the form of a pulse. Outputs (VOUT2).

When the second target signal VOUT1 is output from the first comparator 126 and the second flare signal VOUT2 is output from the second comparator, the logic circuit 150 outputs a high or low signal according to the input of the two signals in the form of pulses. do.

The signal output from the logic circuit 150 is input to the field effect transistor 113 of the automatic gain control circuit 110 to control its amplification level. That is, if the gain of the target signal is large, the amplification level of the field effect transistor 113 is lowered. If the gain of the target signal is small, the amplification level of the field effect transistor 113 is increased to adjust the gain based on the target signal, thereby automatically gaining the gain. Signals VOUT3 and VOUT4 having the same magnitude are always output from the first amplifier 111 and the second amplifier 112 of the adjustment circuit 110.

Therefore, when the target signal is detected, the target signal level is stored through a separate routine, and the target signal is stably used to control the gain level of the automatic gain control circuit so that the target signal can be stably detected even if the target signal is covered by the flare signal. Can be detected.

As described above, according to the target detection circuit according to the present invention, in order to operate the automatic gain control circuit based on the size of the target signal, the size of the target signal is stored in advance, so that other signals obstruct and separate the target signal. By using the stored target signal, the automatic gain control circuit can be stably operated to detect the target signal.

Claims (4)

A first amplifier for amplifying the input first target signal, a second amplifier for amplifying a first flare signal having the same magnitude as the first target signal, and a signal output from the first amplifier to be fed back from the outside Automatic gain consisting of a switching element for varying the amplification level in accordance with the signal, and an attenuator for maintaining the output of the first amplifier and the second amplifier by maintaining the signal output from the switching element at a constant level to adjust the gain of the first amplifier and the second amplifier In the target signal detection circuit comprising an adjustment circuit, A target signal detection circuit that receives the first target signal and the first flare signal by inputting the control signal, converts the signals into pulses, adds the two converted signals, and compares them with a reference signal to output a second target signal. Wow, An initial threshold voltage generation circuit for outputting an initial threshold voltage which is a DC voltage of a predetermined level according to a user's initial input gain setting by an input control signal; A second flare by comparing the detected peak value with an initial threshold voltage output from the initial threshold voltage generation circuit as a reference signal by detecting a peak value of the first target signal output from the target signal detection circuit by an input control signal A flare signal detecting circuit for outputting a signal; And a logic circuit for controlling the amplification level of the switching element of the automatic gain control circuit by adding two signals output from the target signal detection circuit and the flare signal detection circuit. The method of claim 1, The target signal detection circuit, A half wave rectifier for receiving the first flare signal having a sinusoidal shape and rectifying the half wave; A first peak detector for detecting a peak value of the signal output from the half-wave rectifier; A first switch which is switched according to an input control signal and converts a signal output from the first peak detector into a pulse wave form and outputs the pulse wave; A second switch switched according to an input control signal to convert the first target signal into a pulse wave form and output the pulse signal; An adder for adding and outputting signals input from the first switch and the second switch; And a first comparator configured to compare a pulse type signal output from the adder and a reference signal to output a second target signal that is a difference between the two signals. The method according to claim 1 or 2, The flare signal detection circuit, A second peak detector for detecting a peak value of a signal output from the first comparator of the target signal detection circuit according to an input control signal; And a second comparator configured to output a second flare signal that is a difference between two signals by comparing the peak value detected from the second peak detector with an initial threshold voltage output from the initial threshold voltage generation circuit which is a reference signal. Target detection circuit. The method of claim 3, wherein The second peak detector, And at least one capacitor and a resistor so as to store the second target signal by lengthening a time constant.